The greatest cities on Earth are always in motion. Their bustling activity forms a great collective organism, whose shape changes over time. So there's a good reason why we're all fascinated by timelapses of cities — and there's nothing cooler than timelapses of aerial footage. See the world's biggest cities in a whole new way.

1. Chongqing, China, pop.: 28,846,170

2. Shanghai, China, pop.: 24,150,000

3. Karachi, Pakistan, pop.: 23,500,000

4. Beijing, China, pop.: 21,516,000

5. Delhi, India, pop.: 17,838,842

6. Tianjin, China, pop.: 14,722,100

7. Istanbul, Turkey, pop.: 14,160,467

8. Lagos, Nigeria, pop.: 13,400,000

9. Guangzhou, China, pop.: 12,700,800

10. Mumbai, India, pop.: 12,655,220

11. Moscow, Russia, pop.: 12,111,194

12. Dhaka, Bangladesh, pop.: 12,043,977